1. Field of the Invention
This invention relates to an image display apparatus, in which image recorded on an image recording medium such as microfiche is read out with an image sensor or the like and displayed on a display section, and more particularly, to image recording apparatus which permits desired images to be retrieved according to index data on an image recording medium to display retrieved image.
In an analog-type reader/printer for displaying image recorded on a microfiche as image recording medium, by inserting the image recording medium between two glass plates of an X-Y carriage movably provided on a reader/printer body, the X-Y carriage starts to be moved, and an index frame of image recording medium, in which index data is recorded, is projected onto an optical screen when the index frame is located in a projecting optical path. The operator searches the frame number of a desired image frame while looking at index data and inputs that frame number to a keyboard. As a result, the X-Y carriage is moved to locate the desired image frame on the projecting optical path, and the desired image is enlargedly projected on an optical screen. Then, if it is intended to refer to the index frame for observing a different image frame, the X-Y carriage is moved again by turning on an index switch provided on the keyboard. As a result, the index frame is located on the projecting optical path, and index data is projected again on the optical screen.
The analog type reader/printer noted above has to be provided with a large size optical screen for it is necessary to enlarge an image frame of the image recording medium to a size close to the original size and confirm the image data. Therefore, size increase of the apparatus is a necessary liability.
Further, in the analog process it is difficult to process image data freely.
Recently, a digital reader/printer has been proposed, in which an image frame on microfiche is read out with an image sensor or the like, and the read-out image is stored in an optical disk or like memory while it is displayed on a CRT or like display.
With this digital reader/printer, in which the read-out image is displayed on the CRT or like display, no large size screen is necessary. In addition, since the read-out image is stored as digital data, it is possible to obtain various processes of image data.
However, with the prior art analog system noted above, the index data can be instantly referred by merely moving the index frame to a predetermined position of projection with an X-Y stage moved by turning on an index switch. With the prior art digital system noted above, for referring to index data it is necessary to perform a reliable reading operation after the index frame has been moved to a predetermined reading position with movement of an X-Y carriage.
In the retrieval of microfiche, generally index data is referred to very frequently, and the arrangement which permits reference to index data only after reading of the index frame performed subsequent to the movement of the X-Y carriage reduces the efficiency of the retrieval operation, and the advantage of capability various processes of image data can not be substantially made use of.
The present invention has been intended in order to solve the problems in the prior art, and its object is to provide an image display apparatus, which permits digital image processing and can instantly display index data.
Another object of the invention is to provide an image display apparatus, which can display a desired image on an image recording medium in a short period of time.
A further object of the invention is to provide an image display apparatus, which can display image data and index data recorded on an image recording medium with reduced wasteful operation and hence with improved efficiency to permit search a desired image in a short period of time.
To attain the above objects of the invention, there is provided an image display apparatus, which comprises moving means for locating a desired image on an image recording medium to a read-out position, reading means for optically reading out an image and generating an electric signal corresponding to the read-out image, and display means for displaying image stored in the memory means. The memory means includes a first memory for storing image data and a second memory for storing predetermined index data on the image recording medium, and the display means selectively displays data stored in either the first or second memory.
The second memory suitably has a memory capacity of storing images for two or more frames.
Further, suitable index data is stored in the second memory immediately after loading of the image recording medium.
Further, it is possible to change data stored in the memories.
With the construction noted above according to the invention, in which a first memory for storing an image read out by reading means and a second memory for storing index data are provided, no reading operation has to be performed for every index data display.